1. Field of the Invention
The present invention relates to a method of signal detection using delta spectrum entropy, and more particularly, to a method of signal detection through obtaining delta spectrum entropy including time dependent information of frequency spectrum from input signals and then, detecting a target signal among the input signals utilizing thus obtained delta spectrum entropy. The present invention also relates to an apparatus for detecting input signals and a recording medium on which a program for executing the method is recorded.
2. Description of the Related Art
Recently, a method of transforming an input signal of time domain into a signal of frequency domain and then processing thus transformed signal is generalized. The signal processing at the time domain is more efficient when considering an operating amount and processing time. However, the performance of the signal having an SNR of low energy is rapidly deteriorated. Utilizing the frequency characteristic of the signal which is not exhibited at the time domain, the signal processing at the frequency domain exhibits further better performance at the low SNR.
In addition, an input signal processing method utilizing input signal entropy value transformed into a signal of frequency domain, is widely used in a various fields of information processing and signal processing.
For example, spectrum entropy information is widely utilized in various fields including network traffic anomaly detection, an apparatus and a method of finger print classification and finger print recognition, encoding and decoding of entropy, audio signal detection, target monitoring method of signal, and so on.
For example, conventionally, spectrum estimated information is computed at the frequency domain utilizing an input signal. And according to the computed spectrum information, the input signal is judged if it is the desired or undesired signal.
This kind of judging method is widely used in the field concerning the signal detection. Here, a normal signal is the desired signal, while the abnormal signal is undesired signal, e.g. noise.
In particular, most of the system using an audio signal treats the audio signal in the frequency domain.
According to the conventional method, suggested is a method of detecting a signal utilizing a statistic characteristic and auditory sense characteristic of human in processing an audio signal at the frequency domain of the audio signal.
As described above, the method implemented at the frequency domain utilizes information concerning the low frequency component or the high frequency component of the audio signal, or pitch information and hamonic information concerning integral frequency of fundamental frequency.
However, the above-described method is difficult in applying to an instrument of which miniaturization, mobility and real time processing should be guaranteed in an embedded environment of navigation system, PDA, cellular phone, etc. except a personal computer.
In addition, when an input signal is an audio signal, the detecting performance is guaranteed in a clean environment including no noise according to the conventional signal detecting method. However, in an environment including a white noise, the signal detecting performance is remarkably lowered according to the conventional method.